Method and apparatus to continuously separate cut pieces from flexible material

ABSTRACT

A fully addressable vacuum/positive pressure roller may select and remove pattern pieces that have been severed or cut from a web or sheet of flexible material even though the pattern pieces are still embedded within the web, both being supported on a common surface. Vacuum rollers may be disposed along the path of an advancing web with the rollers being oriented such that each roller&#39;s axis of rotation is both orthogonal to the advance direction of the web and orthogonal to the surface normal of the web so that the web travels around at least a portion of the arc of each roller. The vacuum roller for conveying the web or sheet type material includes an external surface having a plurality of apertures there through. A plurality of addressable valves are in corresponding fluid communication with the plurality of apertures. By controlling the state of each of the plurality of valves, the user may selectively address each valve independently in order to achieve a desired state of each of the valves at all times and/or positions during operation.

This application claims the benefit of U.S. Provisional Application No.60/677,244, filed May 3, 2005 and entitled Vacuum Roller.

BACKGROUND OF THE INVENTION

This invention relates to the field of selecting and removing patternpieces that have been severed or cut from a web or sheet of flexiblematerial, while the pattern pieces are still embedded within the web,both being supported on a common surface.

This invention also relates to the field of vacuum rollers where one ormore said rollers are disposed along the path of an advancing web saidrollers being oriented such that each roller's axis of rotation is bothorthogonal to the advance direction of the web and orthogonal to thesurface normal of the web and said rollers are positioned such that theweb travels around at least a portion of the arc of each said roller.

This invention also relates to the field of steering and guiding webs,tapes, sheets and conveyer belts both with uniform material properties,and those with non-uniform material properties.

This invention also relates to the field of effecting or influencing aprocess to be performed on a web, tape, sheet or conveyer belts wherethe level of pressure on the web must be applied in an arbitraryprogrammed manner over the material surface.

The webs or sheets are normally comprised of films, laminates, fiberswoven materials or animal hides as are used in technical textiles,apparel, furnishings, engineering membranes, composite materials such astapes, wovens that may be pre-impregnated with adhesives or linermaterial and nanostructured compositions such as distributed or alignedcarbon nanotubes which may further be embedded in a polymer web orsheet. Semi rigid foils and semi rigid sheet metal webs or pieces mayalso be manipulated with the apparatus described here.

The web or sheet in which the pattern pieces are embedded is supportedon a planar, cylindrical, or curved surface. The vacuum roller axis maybe in relative translational motion to the material support surface. Thevacuum roller has its rotational axis orthogonal to the relativedirection of travel of the material surface and orthogonal to the normalvector of the material surface.

The vacuum roller is rotating so that the surface of the vacuum rollerand the surface of the material are in registration (no relativemotion).

Prior art vacuum roller designs present a variety of methods to achievethe application of selective vacuum to a portion of the arc of a roller.This arc portion is to remain generally stationary with respect to themachine configuration, such that as the roller rotates, its surfaceports are successively ported to either vacuum, pressure or closed.

Most of these designs are intended to provide vacuum retention andmotion to a web or sheet of flexible material by “pulling” vacuumthrough the surface of a roller into the hollow core of the roller. Thecore has a rotating joint at one or both ends that allows the attachmentof a non-rotating vacuum hose to a remote vacuum pump or source.

In the prior art, the general design schemes provide for the “zoning” ofvacuum and or positive pressure to a portion of the arc of the roller.Vacuum is ported to the roller surface to draw the web or sheet intointimate contact with the roller surface. At a pre-determined positionof rotation, usually when the sheet leading edge is tangent to anotherroller, the vacuum is switched to a positive pressure to “push” thesheet or web leading edge away from the current roller onto the nextroller or conveyer. These roller pressure transitions are effected atspecific arc locations and are in effect across the length of the rollerat any specific arc position.

The prior art vacuum roller systems lack the ability to selectivelycontrol the presence of vacuum at each of the surface ports of theroller independently of one another. The prior art fails to provide amechanism to permit roller pressure transitions which do not eitherapply to an entire row of surface ports along the roller or to an entirering of surface ports around the circumference of the roller.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a fullyaddressable vacuum/pressure roller. A vacuum roller for conveying a webor sheet type material, comprises a rotatable roller having an externalsurface. The rotatable roller has a plurality of bores there through,each of which bores terminates at a surface port in the external surfaceof the rotatable roller. A plurality of addressable valves are in fluidcommunication with the plurality of bores. The plurality of addressablevalves is also in fluid communication with both a vacuum source and apressure source. A means for addressably controlling the state of eachof the plurality of valves is provided to selectively permit the fluidcommunication through a respective one of the bores between the vacuumsource or pressure source and a respective one of the surface ports. Onemethod to addressably control each of the plurality of valves is toutilize a programmable controller programmed with software that performsthe switch sequencing and a data base or data file that the softwareaccesses, the data represents the desired state of each of the valves atall times and/or positions during operation.

A valve assembly is provided for use in a rotatable vacuum roller havingan external surface and a plurality of bores there through, each ofwhich bores terminates at a surface port in said external surface of therotatable roller. The valve assembly comprises a plurality ofaddressable valves each of which is in fluid communication with a vacuumsource and a pressure source and one of said surface ports. A means foraddressably controlling the state of each of the plurality of valves isprovided to selectively permit the fluid communication through arespective one of the bores between the vacuum source or the pressuresource and a respective one of the surface ports.

The present invention describes a vacuum roller that allows theselective application of vacuum or pressure to any desired surface portaround the roller's circumference and along the roller's length. This isprogrammable so that any selected surface port may have its statechanged at any time during operation. This “porting” is dynamic. Theaddressable valve in fluid connection with each surface port can beswitched instantly while the roller is rotating.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is a perspective view of a schematic of an apparatus inaccordance with an embodiment of the present invention.

FIG. 1B is a cross-sectional view of the roller shown in FIG. 1A takingalong lines 1B-1B.

FIG. 1C is an enlarged view of a portion of the roller shown in FIG. 1B.

FIGS. 2A and 2B are perspective and top views respectively of an exampleof pressure distribution along a single row of surface ports.

FIGS. 3A and 3B show a conveyorized, two axis cutting system thatincorporates an example of the system described herein.

FIGS. 4A and 4B show an addressable vacuum roller having an array ofsurface ports in accordance with one example of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning now to the drawings, and first with reference to FIGS. 1A, 1B,and 1C, an apparatus according to an embodiment of the present inventionis shown generally by reference numeral 101. There is provided a fullyaddressable vacuum/pressure roller. As used herein, the word“addressable” refers to the identification of a location by an addressor a name in order to facilitate information transfer. The use of anaddressable control mechanism provides the ability to independentlyswitch any single surface port (also referred to as aperture) to eithervacuum, pressure or off (closed) without reference to the state ofneighboring surface ports. Addressable control enables a vacuum rollerto function with precision and specificity facilitating for examplepicking up and releasing work pieces having complex shapes from within aweb or sheet.

Also, although the examples discussed herein include roller systems, itis envisioned that the addressable controls may be incorporated in otherendless surfaces in circuitous motion applications includingconveyorized belt systems generally. The use of addressable valves canbenefit this entire class of moving systems that move in a loop.

Returning again to FIGS. 1A, 1B and 1C, a Vacuum roller 101 forconveying a web or sheet type material (Not Shown), comprises arotatable roller 102 having an external surface 103. The rotatableroller 102 has a plurality of bores 104 there through, each of whichbores 104 terminates at a surface aperture or port 105 in the externalsurface 103 of the rotatable roller 102. The surface ports 105 maypreferably be disposed in a grid pattern of rows along the longitudinaldirection of the rotatable roller 102 and rings (or columns) around itscircumference. The rows are parallel to the axis of the roller andperpendicular to the direction of rotation of the roller.

A plurality of addressable valves 107 are in fluid communication withthe corresponding plurality of bores 104. The plurality of addressablevalves 107 is also in fluid communication with a vacuum source 108. Thisis achieved by having a vacuum manifold 109 inside a rotating roller.The vacuum manifold may be non-rotating, but is usually anaxis-symmetric coaxial tube that rotates with the rotatable roller 102to provide both a vacuum manifold and act as the primary structuralsupport for the roller. A rotating slip joint is used at the end of theroller to allow fluid communication of the non-rotating vacuum source108 with the rotating roller's vacuum manifold 109.

It is preferable in an alternative embodiment to provide, in addition tothe vacuum source, a positive pressure source 110. The pressure sourcewill enable positive air pressure to be used to discharge a piece of webmaterial from the vacuum roller by progressively pushing the piece awayas the web and roller advance. In this embodiment, the plurality ofaddressable valves 107 is also in fluid communication with a pressuresource 110. This is achieved by having a pressure manifold 111 inside arotating roller. The pressure manifold 111 may be non-rotating, but isusually an axis-symmetric coaxial tube that rotates with the rotatableroller 102 to provide both pressure and act as the primary support forthe roller.

Vacuum and pressure are commuted from remote pumps (not shown) andcompressors (not shown) to the rotating vacuum manifold 109 and pressuremanifold 111 through rotating slip joints 112 located at the end of theroller shaft. This design provides for both angular and axial zoning ofvacuum or pressure to the external surface 103 of the rotatable roller102.

FIG. 2A shows a representative pressure distribution diagram along asingle row 206 of an addressable vacuum roller. The high pressure zones201 show positive pressure intended to push away web portions thatintersect row 206, the low pressure zones 202 show vacuum intended toretain web portions that intersect row 206.

Successive rows would generally have different pressure distributionprofiles valving vacuum for example to ports that are in contact withportions of the web that are to retained by the roller, positivepressure to portions of the web that are to be removed from the roller,and closing the valve where no material is in contact with the roller(not shown).

Vacuum and pressure levels are shown on the diagrams with magnitudes of−200 mb for the vacuum and +200 mb for the pressure. However, these areshown as examples only. Appropriate levels would need to be investigatedto be compatible with the web or sheet material to be manipulated and toallow the addressable vacuum roller to function as intended.

With reference to FIGS. 2A and 2B, the following example is by way ofillustration only and is not intended to be limiting. A vacuum rollercan be provided which is suitable for the handling of 48″ wideplasticized vinyl webs for example 0.030″ thick. The vacuum roller inthe present example has an outside diameter of 10.0 inches and an activelength of 48.0 inches. The axial port pitch of the surface ports is 2.0inches which corresponds to 25 equally spaced surface apertures or portsalong the roller's axis, the circumferential port pitch of the surfaceports is about 1.6 inches, which corresponds to 20 equally spacedsurface ports around the roller's circumference. The surface speed atwhich the web would travel while passing around the rotatable roller is40.0 inches/second. With these specifications, the rotatable rollerwould have 500 surface ports. A programmable controller suitable forcontrolling the embodiment of the invention which selectively providesboth vacuum and pressure in the rotatable roller would require 1000output switches, 500 two state switches to select vacuum and 500 twostate switches to select positive pressure. In the case of a vacuum onlydesign, the programmable controller would require 500 two state outputs.

An alternative control system could provide for a switching matrix thatutilizes a row and column multiplexer and a toggle valve at each surfaceport. Such a multiplexed system would utilize momentary signal levels toswitch valve states, requiring only 45 outputs—25 for the axialaddresses and 20 for the circumferential addresses.

Control Method

A means for addressably controlling the state of each of the pluralityof valves is provided to selectively permit the fluid communicationthrough a respective one of the bores between the vacuum source and arespective one of the surface apertures or ports. A large number ofvalves and associated ports is controlled by a valve control system suchas a remote dedicated computer or programmable logic controller (PLC),or an embedded control system or combination thereof, with the requiredinput/output hardware and software to perform the switch sequencing. Thevalve control system discussed by example herein is an electroniccontrol system. Other valve control systems based on pneumatics ormechanical linkages or hybrid combinations of control systems may alsobe employed

In the examples of web and sheet applications that follow, the Xdirection is along the long axis of the web also the direction oftravel, the Y direction is orthogonal to both the X axis and the websurface normal vector and the Z axis is normal to the surface of the webor sheet. Since these webs or sheets are generally flexible, thecoordinate frame indicated here is relative to the surface of the web orsheet at any one point on its surface.

The control system software is limited to the function of 1) knowing thestate of each of the valves (C=closed, V=vacuum and P=positivepressure), 2) knowing the x-position of the roller surface with respectto the x-position of the web and 3) being able to read a command filethat describes the boundaries of the cut pieces in x, y coordinatesrelative to the web origin.

1) Knowing the state of each valve is most easily achieved by settingall of the valves into a known position prior to operation and thentracking the state changes invoked by the control system within thecontroller software.

2) The x-position of the roller surface with respect to the x-positionof the web is achieved by either starting both at pre-determinedpositions or, at a time when the roller and web are not moving theoperator can enter the current x-position of both the web and the rollerinto the controller software. After either of these initializations arecompleted an encoding device tracks the roller rotational position andthe control system either tracks the web or sheet x-position by means ofan encoding devise or the controller software calculates the webx-position based on the roller's rotational motion and estimates of webmotion relative to the roller surface, if any.

A vision system could be utilized to scan and inspect the moving webupstream of the vacuum roller. This vision system would detect thepositions of the cut lines and also detect flaws in the web material orin the cut lines, and construct the appropriate commands to allow thevacuum roller to position and switch the valve states so as tomanipulate different portions of the web as intended, the cut piecesremoved for further handling and flawed portions of the web discarded.

3) The control software performs a simple raster scan on the web andproduces an image of the vacuum roller valve locations superimposed onan image of the pattern pieces. The vacuum roller valve state at eachvalve location is then determined and stored for retrieval when thevacuum roller is in motion.

As the vacuum roller rotates during operation, the control systemdetermines the timing of the valve state transitions based on thex-position of the roller from the encoder and the stored valve states.

An example vacuum roller command file fragment required to operate thevacuum roller valve structure shown in FIGS. 4A and 4B to pick up adiamond shaped pattern piece out of a web is shown below. row column −>Y axis V 1 C C C C C C C C C C C C C C C C C C C C C C C C X 2 C C C C CC C C C C C C C C C C C C C C C C C C axis 3 C C C C C C C C C C C V C CC C C C C C C C C C 4 C C C C C C C C C C V V V C C C C C C C C C C C 5C C C C C C C C C V V V V V C C C C C C C C C C 6 C C C C C C C C V V VV V V V C C C C C C C C C 7 C C C C C C C V V V V V V V V V C C C C C CC C 8 C C C C C C C C V V V V V V V C C C C C C C C C 9 C C C C C C C CC V V V V V C C C C C C C C C C 10 C C C C C C C C C C V V V C C C C C CC C C C C 11 C C C C C C C C C C C V C C C C C C C C C C C C 12 C C C CC C C C C C C C C C C C C C C C C C C C 13 C C C C C C C C C C C C C C CC C C C C C C C C 14 C C C C C C C C C C C C C C C C C C C C C C C C 15C C C C C C C C C C C C C C C C C C C C C C C C

Where C identifies a closed port, no fluid contact with either thevacuum or pressure manifold.

and V identifies surface port locations that are in fluid communicationwith the vacuum manifold.

Control Method—Example with Multiplexed Switch Array

For simplicity, the example described here is for a vacuum roller thatis able to provide only vacuum (port valve open) or no pressure (portvalve closed) to any one of its surface ports.

FIG. 4A shows an addressable vacuum roller 101 with an array of surfaceports 105 in fluid communication with an addressable valve (not shown),the addressable valve can switch the port from fluid communication to avacuum source (not shown) or to a closed state where no air flow isallowed to pass through the port.

As the roller 101 rotates, its rotational position is reported to thedigital control computer 441 by an absolute digital encoder 440. Thecontrol computer compares the roller position to the position in apre-calculated file of the valve states required to be switched alongeach row as that row passes a specific point in the roller's rotation,usually a point where the web or a cut piece is either entering orexiting tangent to the roller's surface.

The control computer transmits signals 411 to a column select switchbank 413 closing any number of normally open switches 405. At theappropriate time, the control computer transmits signals 412 to a rowselect switch bank 414 closing a single normally open switch 406.

The selected switch closures allow current to flow from the electricalpower source 426 through the switch 405 out to the roller valve (notshown) in fluid communication with the surface port 105, the currentthen flows along the conductor 415, through the valve's solenoidactuator (not shown), then along conductor 416 to the row select switch406 then to the electrical power source's ground 427.

The valve utilized here is of a toggle valve design—the current flowingthrough the valve's solenoid switches the surface port 105 into fluidcommunication with the vacuum source. When the electrical current isreleased, when either switch 405 or 406 are opened, the valve remains inthe state where vacuum is ported through to the surface port 105. Theport is closed when a mechanical link closes all ports along a specificrow simultaneously (not shown).

The multiplexed design described above allows the selective actuation ofany valve such that the roller can apply selective vacuum force to anysurface port as required.

Utilization—Vacuum Roller Arrangement to Separate Cut Pattern Piecesfrom a Passing Web

FIGS. 3A and 3B show a conveyerized two axis cutting system as arecommonly utilized to continuously cut web material from rolls whereuncut roll goods in web form 313 are supplied onto a flexible airpermeable conveyer 321 in fluid communication with a vacuum manifold315. The conveyer transports the material into a cutting zone where a 2axis cutter carriage 317 cuts pattern piece boundaries 328 inside of theweb 312. The web is comprised of pattern pieces 328 embedded within butsevered from the surrounding scrap 329.

The web is advanced until it is under a first vacuum roller 300 of atraditional zoned vacuum roller design. This roller applies vacuum toit's surface starting at the position indicated by 331, the vacuum levelis sufficient to pull the entire web off of the conveyer and advance theweb to position 332 where roller 300 closes successive axial rows ofsurface ports as they pass position 332, so that the entire web can bepicked up by the first addressable vacuum roller 301. Addressable vacuumroller 301 applies vacuum starting at position 332 to pull the entireweb into intimate contact and away from roller 300.

Roller 301 then selectively switches only the surface ports that areadjacent to the pattern pieces at position 333 from vacuum to eitherclosed or to positive pressure, the surface ports that are under thescrap portion of the web are maintained in fluid communication with thevacuum source to maintain intimate contact with roller 301. Addressablevacuum roller 302 applies selective vacuum to surface ports that areadjacent to the pattern pieces as they pass by position 333. As each rowof addressable vacuum roller 302 passes location 334, all surface portsalong that row are closed such that pattern pieces 328 in contact withroller 302 transfer to a conveyer removal system 340. As each row ofvacuum roller 301 passes position 335 all surface ports along that roware closed, releasing the scrap portions of the web 329 onto anappropriate scrap removal system 350.

The apparatus described above comprises an effective system to separatecut pattern pieces from a web and deposit the pattern pieces onto anappropriate take-away system while also sending the scrap to anappropriate location. A more advanced system employing a greater numberof addressable vacuum rollers would allow the separation of multiplelayers of pattern pieces and scrap. Such a system would have multiplearrangements of addressable vacuum rollers, each such arrangement wouldbe of the same general configuration as described above and presented inFIG. 3A and FIG. 3B. Additionally, while the web is shown moving acrossthe roller, it is also possible for the web to be stationary and havethe roller move across the web. Still further, they may both moverelative to each other at the same time.

Utilization—Differential Pressure to Aid an Addressable Process on a Web

Further, the addressable vacuum roller disclosed in the presentinvention may be utilized to apply selective controlled normal force toportions of a web where such variable pressure across and within a webis intended to even out the tensions of a web with non-uniform elasticproperties such as a web with embroidered emblems embedded within or aweb or sheet with non-uniform structural reinforcement.

These and other objects, aspects and features of the present inventionmay be realized by the provision of a vacuum roller. As will beappreciated by one of ordinary skill in the art, an apparatus accordingto the invention may be suitable for use in any field or industryrequiring selecting and removing pattern pieces that have been severedor cut from a web or sheet of flexible material. Accordingly, thepresent invention should not be viewed as limited to any particular useor use in any particular industry. While the foregoing describes whatare considered to be preferred embodiments of the present invention, itis understood that various modifications may be made thereto and thatthe invention may be implemented in various forms and embodiments, andthat it may be applied in numerous applications, only some of which havebeen described herein. It is intended by the following claims to claimall such modifications and variations which fall within the true scopeof the invention.

1. An endless surface in circuitous motion system comprising: an outersurface having a plurality of apertures configured in the surface; acorresponding plurality of valves wherein each aperture has a valve influid communication therewith, and further wherein each valve is influid communication with at least one of a vacuum source and a positivepressure source; and a valve control system connected to each valve,wherein, each individual valve may be independently switched by thevalve control system between being in a state of switched closed, andswitched to vacuum or switched to positive pressure without reference tothe state of any other valve.
 2. An endless surface in circuitous motionsystem as described in claim 1, wherein each valve is in fluidcommunication with both a vacuum source and a positive pressure source,and wherein each valve may be independently switched by the valvecontrol system between being in a state of switched closed, switched tovacuum, and switched to positive pressure.
 3. An endless surface incircuitous motion system as described in claim 1, wherein the outersurface is the outer surface of a rotating roller.
 4. An endless surfacein circuitous motion system as described in claim 1, wherein theelectronic control system is either a dedicated computer or aprogrammable logic controller.
 5. An endless surface in circuitousmotion system as described in claim 3, wherein the vacuum source is avacuum manifold inside the rotating inside the rotating roller.
 6. Anendless surface in circuitous motion system as described in claim 3,wherein the positive pressure source is a positive pressure manifoldinside rotating roller.
 7. An endless surface in circuitous motionsystem as described in claim 1, wherein the valve control system isremote from the endless surface.
 8. An endless surface in circuitousmotion system as described in claim 1, wherein the valve control systemis embedded in the endless surface.
 9. A method of separating pieces offlexible material cut from a web comprising the steps of: providing avacuum roller comprising an outer surface and a plurality of aperturesconfigured in the surface, a corresponding plurality of valves whereineach aperture has a valve in fluid communication therewith, and furtherwherein each valve is in further communication with a vacuum source;providing a valve control system connected to each valve, wherein eachindividual valve may be independently switched by the valve controlsystem between being in a state of switched closed and switched tovacuum without reference to the state of any other valve; Moving the webacross the vacuum roller or moving the vacuum roller across the web,wherein the roller is disposed across the direction of relative motionof the web and vacuum roller; and selectively controlling the valves inthe vacuum roller to attract or not attract portions of the web to thesurface of the roller.
 10. A method as described in claim 9, furthercomprising: providing a positive pressure source also in fluidconnection with each valve, wherein each valve may also alternatively beswitched to a state of switched to positive pressure.
 11. A method asdescribed in claim 9, further comprising: providing a plurality ofvacuum rollers disposed across the direction of relative motion of theweb and vacuum roller, and moving the web across the plurality ofrollers or moving the rollers across the web, and selectivelycontrolling the valves in the plurality of rollers to attract or notattract portions of the web to the respective surfaces of the respectiverollers.
 12. A method as described in claim 9, wherein the apertures aregenerally uniformly disposed over the surface of the roller.
 13. Anendless surface in circuitous motion system as described in claim 1,wherein the apertures are generally uniformly disposed over the surfaceof the roller.